Effect of diltiazem on recurrent spontaneous angina after acute myocardial infarction

This study examined the effects of diltiazem, a calcium antagonist, on suppressing spontaneous angina following acute myocardial infarction. Twelve patients developed rest angina within a few days after the onset of acute myocardial infarction, which was associated with transient S-T segment elevation. A 24-hour recording of electrocardiogram revealed cyclic S-T segment elevation with or without chest pain in all patients. A selective coronary arteriography was performed in seven patients which demonstrated no critical stenosis, despite acute myocardial infarction, in three patients. In one of these three patients, coronary artery spasm was induced by ergonovine in the vessel supplying the acutely infarcted area. These clinical features suggested that spontaneous angina in these patients probably was caused by spasm of the coronary artery. Diltiazem suppressed rest angina as well as painless cyclic S-T segment elevation completely in all 12 patients. The replacement of diltiazem with placebo in two patients caused the recurrence of rest angina. Thus, we conclude that diltiazem is effective in the treatment of postinfarction angina caused by coronary artery spasm.